The wet gasket on the float bowl and black spark plugs indicate the problem could simply be a sunk/heavy float, causing it to run rich, also explains why mixture screws have no authority.
Find someone to repair the carb.
Good luck .
I sanded the airhorn casting mating surface and I don't think it is seeping any gas now. The clip that holds the float hinge rod may have been interfering with the air horn seating fully against the body so I adjusted that also. The brass floats seem fine, no holes.
I think over time the tabs with the holes for the airhorn screws can bend under the force of the screws and cause the casting to not be flat.
